Protector for x-ray tubes



April 28, 1925.

E. L. EDWARDS PROTECTOR FOR X RAY TUBE Filed Apiil '7, 1921 atbozmgy til Patented Apr. 28, 1925.

EDWIN L. EDWARDS, F INDIANAPOLIS, INDIANA, A$SIGNQR TO Iii-RAY couronarron, or INnIAnaPoLIs, INDIANA, la oon-ronnrrou OF INDIANA.

PROTECTOR FOB X-RAY TUBES.

Application filed April 7,

To all echo m. it may concern:

Be it known that I, EDWIN L. Enwanns, a citizen of the United States, residing at Indianapolis, in the county of Marion and f ltate of Indiana, have invented a new and useful Protector for X-Ray Tubes, of which the following is a specification.

In the operation of X-ray machines, the patient or the operator is frequently shocked, and sometimes severely injured or even killed, by getting too close to the high voltage end of the tube. While this sometimes happens through carelessness, it frequently happens through failure to appreciate the nature of the high voltage used,'or through some involuntary movement, especially on the part of the patient, at the time the tube starts working, for frequently the patient will throw up his hands when h sees the tube light up.

It is the object ofmy present invention to provide a full and sufficient protection for the high-voltage end of an X-ray tube, which operates both by insulation to prevent the current from jumping from such highvoltage end to the operator or patient, and by grounding and carrying away any currents which "may succeed in jumping in spite of the insulation. By this doubleprotectiou, the danger "from the use of X-ray tubes practically eliminated.

In carrying out my invention, I provide an insulating shield at the high-voltage end o't an Xa-ay tube, andprovide in addition and somewhat further away from such highvoltage end a grounded metallic shield. Both shields are carried by and partake of the adjusting movements of theX-ray tube. Either or both shields may completely encircle the tube, or may be open at the top, as desired, as the greatest danger is of touching the tube from the bottom or sides.

The accompanying drawing illustrates my invention. Fig. 1 is a side view of a dental X-ray machine in operation, showing its relation to dentist and patient, and showing one form of protector for the high-voltage end 01' such tube; Fig. 2 is a. longitudinal section through an X-ray tube and its mounting, equipped with my protector; Fig. 3 an enlarged transverse section on the line 8-3 of Fig. 2; Fig. 4 is a perspective view showing a modified form of protector open at the top; Fig. 5 is a detail of amodification in which the lower end of the hi h- 1921. Serial No. 459,273.

voltage supply wire to the tube is attached somewhat differently from the way it is shown in Fig. 2; and Fig-. 6 is a transverse section through a modified form of protector, in which the metallic shield is errbedded in the insulating shield.

The X-ray tube 10 is carried by an adjustable carrier 11 mounted on a suitable cabinet 12, in which is mountedthe necessary apparatus, including the transformer, for supplying high-tension currents to the conductor 13, which leads over suitable insulating support rods 14 to the high-tension end 15 of the Xray tube shown, this hightension end is usually provided with a radiator 16 for dissipating the heat produced. The X-ray tube proper is usually mounted in a lcadglass holder '17, for protecting the operator and the patient from X-rays except at the point from which it is desired that they should be projected; this lead-glass holder is commonly used, butthe higlrtension end 15 with the radiator 16 is lonted outside of it, and the protection for which the present invention is intended is from higlrvoltage currents and not from X-ray burns. The other side of the X-ray tube shown is connected by a conductor 18 to the grounded side of the circuit, indicated by having the cabinet 12 grounded at 19.

The apparatus within the cabinet may be controlled by a portable hand switch 20, leading to the cabinet by a flexible conductor 21 so that it'may he carried by the operator 2?. to any suitable position. The tube 10 adjusted to the patient 23, who is seated in the chair 24, which may be. grounded in the usual manner. All the construction so far described may be of any standard or con venient type, as it is merely incidental.

The high-voltage end 15 of the tube, and the radiator 16, are protected and guarded by my double. shield against being accidentally touched. In. the forms shown in Figs. 1, 2, and 3, this double shield comprises a tube 25, of insulation, which completely surrounds the high-voltage end of the tube, the radiator 16, and the holder 17 near such high-voltage end, and which projects some distance beyond such high-voltage end so that the operator will not touch such end through the open end of the tube 25. This tube is of some suitable insulating material, and is carried by the carrier 11, as by being bolted thereto at one end. Supplementing this insulating shield I provide a conducting shield 26, suitably made o't sheet metal, which conducting shield is also bolted to the carrier ll and thereby grounded. The conducting shield 26 as shown is trough-shaped, open at the top, and serves to prevent the operator or the patient from touching the insulating shield 25 or the high-voltage end of the tube. The insulating shield is preferably provided with ventilating openings 27 near the end by which it is supported, for permitting air cire-ula tion to cool the X-ray tube and its radiator 16. hen the insulating shield is tubular, it supports a conductor 28 which extends through its wall and is provided on the outside with aloop 29 to which the conductor 13 may t attached, and is provided on the inside with a flexible metal member 30 which will bear against the radiator 16, thus forming a connection to the high-voltage end of the tube. The conductor 28 may be unprotected, as shown in Fig. 2, or may be located in a lateral boss 31 0t insulation, projecting from the insulating tube 25, as shown in Fig. 5.

If desired, the insulating shield need not project entirely around the high-voltage end of the tube, but may be open at the top, as the insulating shield 25 is shown in rig. at. In this figure, both the insulating shield 25 and the grounded conducting shield 26 are trough-shaped, open at the top. lVith this arrangement, the conductor 13 may be connected directly to the high-voltage end 15 of the X-ray tube.

If desired, the insulating and conducting shields may be combined into a unitary structure. This is shown in Fig. 6, where a. tubular conducting shield 32, which may be a screen, is embedded in the wall of a tubular insulating shield 33. This structure may be formed by an inner insulating tube 34 on the outside of which is slipped the conducting tube or screen 32, upon which is slipped an outer insulating tube 35 embedding the conducting tube 32 between the inner and outer insulating tubes 34 and 35. The conducting tube 33 is grounded in the same way as is the trough-like conducting shield 26 of the other forms.

In operation the insulating shield 25, 25, or S lordinarily prevents any high-voltage currents from jumping either from the highvoltage end 15 of the tube or from the radiator 16. For smaller tubes it may sometimes be suflicient to use this insulating shield alone. By itself, it prevents the operator or patient from touching the charged parts, save from the top when the trough form of conducting shield is used as in I t. I prefer, however, to use the grounded conducting shield 26 or 32 in addition, outside of the insulating shield. If the insulation breaks down, as under an excessively high voltage produced by a surge on the line, any spark which jumps in spite of the insulating shield strikes and is caught by such grounded conducting shield, and is carried harmlcssly to the ground. The grounded conducting shield prevents the patient or operator -trom touching the insulating shield, as well as taking all the sparks which jump from the high-voltage end of the tube, thus doubly protecting the patient and the operator; and the insulating shield serves under normal circumstances to prevent the sparks from jumping out even to the conducting shield, thus normally preventing the patient and the operator from being even, startled by the jumping of a spark.

I claim as my invention:

1. A protector for X-ray tubes, comprising an insulating shield which guards the high-voltage end of an X-ray tube, and a grounded conducting shield outside of said insulating shield, both said shields extending beneath and upward on both sides of said high voltage end and being fixed relatively to the X-ray tube, said conducting shield being spaced from said insulating shield in the vicinity of said high-voltage end.

2. A protector for X-ray tubes, co1nprising an insulating shield which guards the high-voltage end of an X-ray tube, and a grounded conducting shield outside of said insulating shield, both said shields being fixed relatively to the X-ray tube, said conducting shield being spaced from said insulating shield in the vicinity of said highvoltage end.

In witness whereof, I have hereunto set my hand at Indianapolis, Indiana, this 23rd day of March, A. D. one thousand nine hundred and twenty-one.

EDIVIN L. EDIVARDS. 

